A color-matching system using a computer is publicly known because it is disclosed in the specification of U.S. Pat. No. 3,601,589. The above-identified U.S. Patent discloses a method in which the total spectrum reflectance of an unknown color panel is decided by a spectrophotometer, the reflectance is sent to a computer, and the computer mathematically processes the previously-stored data showing the K-value (showing “light absorbing coefficient”) and S-value (showing “light scattering coefficient”) of a pigment and performs logical color-matching.
The contents disclosed in the above-identified U.S. Patent relates a set of calculation procedures. That is, according to the calculation procedures, it is possible to calculate the K-value and S-value of a set of wavelengths and moreover, decide a set of pigments so that the K-value and S-value of the pigments become equal to the K- and S-values of an unknown color for each wavelength of the wavelength set. This is a basic color-matching algorithm also used for other spectrophotometric color-matching systems.
The system according to the above-identified U.S. Patent has problems in that, first, the system is very expensive and it is difficult to maintain the system, and second, the system performs logical color-matching using the data obtained from unknown and already-known pigments of unknown colors. That is, a final color obtained by mixing pigments in accordance with a calculated color value may become a color different from the above unknown color. Therefore, the above color-matching formula is usually a primary mathematical approximation method and therefore, it is necessary to correct and adjust the system by correcting the software that is a part of the system.
To improve the above-described system, Japanese Patent Laid-Open No. 153677/1988 discloses a method and an apparatus of analyzing a selected color by using a portable color meter, storing the color data showing the hue, chroma, and brightness, connecting the color data in the color meter to a computer, storing a plurality of usable color formulas (paint blending) in the computer, storing the color data showing the hue, chroma, and value (brightness) of each paint designated by the stored usable color formulas in the computer, comparing the color data of the selected color received from the color meter with the stored color data showing the stored usable color formulas to find the best approximation matching, selecting a stored color formula shown by the color data found as the best approximation matching, and thereby color-matching the selected color.
Moreover, the number of brilliant paint colors of automobiles has been increased in which aluminum powder or brilliant mica powder is blended from the viewpoint of diversity of personal likeness or improvement of beauty culture. When performing color-matching to refinish-apply the brilliant paint color, the color-matching accuracy is not sufficient in the case of the color-matching method disclosed in Japanese Patent Laid-Open No. 153677/1988. Thus, there has not been any high-accuracy color-matching method of a brilliant paint color using a computer.
It is an object of the present invention to provide a computer color-matching method capable of color-matching a brilliant paint color at a high accuracy. It is another object of the present invention to provide a computer color-matching apparatus that can be used for the computer color-matching method.